If you look at Switzerland, you'll see a state that has existed continuosly since the middle-ages - sure, the dimension of the country has changed, the political system has evolved, the culture of the population is much different etc but today switzerland has a direct link with its past.

That's not the true for many contemporany countries. What type of disappeared states would you like to see today (evolved to match today society, though)?

Possible example of what I mean are pharohs' egypt, the knights of malta, the byzantine empire etc